Erik Jensen

• Geologist PhD
• PostDoc Position at Universidad Católica del Norte (Chile)

This study focuses on quantifying the probability of debris flows or "alluvial activation" along the subsidiary sub-basins of the Maipo River. The Maipo River basin, where the city of Santiago is located, accommodates 35% of the national population. For an appropriate quantification of the risk posed by these phenomena, it is crucial to first chara...

A medida que la población crece y se expone a amenazas más dañinas y frecuentes en un clima cambiante, las naciones deben adaptarse y decidir bien qué, cómo y dónde construir. Para esto, se requiere una mirada integrada e informada de todas las amenazas que acechan al territorio, y así planificar soluciones de adaptación para la infraestructura pre...

Predicting fast mass wasting processes such as landslides is often challenging because of their apparently random occurrence and complex non-linear interactions between in-situ and conditioning parameters. Traditional analysis using susceptibility maps have shown to be a useful tool for identifying parts of the territory that could be more prone to...

The trench-parallel Atacama Fault System (AFS) evidences a long history of deformation since the Cretaceous in the Coastal Cordillera of northern Chile. Conspicuous fault scarps are expressed in the topography of this cordillera attesting to the most recent fault activity, characterized by normal faulting. Particularly, between 23°-25°S, metric fau...

The Coastal Cordillera in northern Chile forms a structural bulge that overlies the downdip part of the seismogenic zone. Along this cordillera from Arica to Antofagasta, two main structural domains are present: one from Arica city to the Loa River mouth dominated by trench orthogonal faults, and the other from the Loa River mouth to Taltal charact...

Fault zone architecture and its internal structural variability play a pivotal role in earthquake mechanics, by controlling, for instance, the nucleation, propagation and arrest of individual seismic ruptures and the evolution in space and time of foreshock and aftershock seismic sequences. Nevertheless, the along-strike architectural variability o...

Fault zone structure is one of the controlling factors of earthquake nucleation and arrest, seismic sequence evolution (i.e., foreshock and aftershock), rupture speed and length, and ground motion and seismic radiation pattern. Here we describe the internal structure of the Bolfin Fault Zone (BFZ), a >40-km-long seismogenic, splay fault of the sini...

How major crustal‐scale seismogenic faults nucleate and evolve in crystalline basements represents a long‐standing, but poorly understood, issue in structural geology and fault mechanics. Here, we address the spatio‐temporal evolution of the Bolfin Fault Zone (BFZ), a >40‐km‐long exhumed seismogenic splay fault of the 1000‐km‐long strike‐slip Ataca...

Tectonic pseudotachylytes are thought to be unique to certain water–deficient seismogenic environments and their presence is considered to be rare in the geological record. Here, we present field and experimental evidence that frictional melting can occur in hydrothermal fluid–rich faults hosted in the continental crust. Pseudotachylytes were found...

How major crustal-scale seismogenic faults nucleate and evolve in the crystalline basement represents a long-standing, but poorly understood, issue in structural geology and fault mechanics. Here, we address the spatio-temporal evolution of the Bolfin Fault Zone (BFZ), a >40-km-long exhumed seismogenic splay fault of the 1000-km-long strike-slip At...

Understanding how major crustal-scale seismogenic faults nucleate and evolve in crystalline basement from the viscous to the brittle realm represents a long-standing, but still poorly constrained, target in structural geology and fault mechanics. Here, we addressed the spatio-temporal evolution of the Bolfin Fault Zone (BFZ), a >40-km-long seismoge...

The complex process of tip-propagation and growth of natural faults remains poorly understood. We analyse field structural data of strike-slip faults from the Atacama Fault System using fracture mechanics theory to depict the mechanical controls of fault growth in crystalline rocks. We calculate the displacement-length relationship of faults develo...

Pseudotachylytes (i.e., solidified frictional melts) remain the only unambiguous signature of seismic slip in the rock record so far. However, pseudotachylytes are considered to be rare in the geological record and found discontinuously along faults. Here we describe, to our knowledge, the first pseudotachylytes ever found in South America. The ps...

The relationship between hydrothermal fluids and fault development is studied through a petrographic analysis of faulted veins in an open-pit copper mine, Radomiro Tomic (RT), northern Chile. Brittle deformation in RT was initiated with the formation of veins, disrupting low-strain crystal-plastic deformation. Following cooling, shear fractures pro...

The geometry of fault zones (e.g. fault surface roughness, fault rock distribution, network of secondary faults and fractures) is one of the main factors controlling earthquake nucleation, rupture speed and length of main shocks, foreshock and aftershock evolution, ground motion and seismic radiation pattern. Despite the pivotal role that fault geo...

ENGLISH Research aimed to answer the general question: “How do the hydrothermal fluids affect in the mechanics and the internal structure of faults in crystalline rocks?”. Faults from two fault systems have been used: Bolfin Fault (Atacama Fault System) and Faults of Radomiro Tomic Deposit (Domeyko Fault System). The first case consists of faults d...

In continental margins, large-scale, strike-slip fault-systems resulted from oblique subduction commonly exhibit a complex pattern of faulting where major faults define the inland boundary of tectonic slivers that can be detached from the margin. In turn, subsidiary faults bound and define internal tectonic blocks within the sliver which are expect...

Fluid-flow migration in the upper crust is strongly controlled by fracture network permeability and connectivity within fault zones, which can lead to fluid-rock chemical interaction represented as mineral precipitation in mesh veins and/or mineralogical changes (alteration) of the host rock. While the dimensions of fault damage zones defined by fr...

Faults architecture and their permeability related fractures play a first order role in fluid-flow migration throughout the upper crust. Commonly, the interaction between fluid-flow migration and host rock is reflected as mineral precipitation in a vein mesh and/or as mineralogical changes (alteration) of the host rock. Often, however, the relation...

Fault development models are crucial to predict geometry and distribution of fractures at all scales. We present here structures related to the development of the Bolfín Fault in the Atacama Fault System (AFS), covering a range of scales of 7 orders of magnitude. The AFS is a 1000 km-long trench-parallel fault system located in the Andean Forearc....

1] Knowledge of the spatial extent of damage surrounding fault zones is important for understanding crustal fluid flow and also for understanding the physical processes and mechanics by which fault zones develop with slip. There are few data available on the scaling of the fault damage zone with fault displacement, and of those that exist, deriving...

Cited By (since 1996): 5, Export Date: 24 July 2012, Source: Scopus, doi: 10.1016/j.jsg.2011.03.004, Language of Original Document: English, Correspondence Address: Arriagada, C.; Departamento de Geología-Centro de Excelencia en Geotermia de Los Andes (CEGA-FONDAP), Universidad de Chile, Plaza Ercilla 803, Santiago, Chile; email: cearriag@cec.uchil...

Fault development models are very important to predict geometry and distribution of fractures at all scales. However, models based on structures from microns to km are relatively scarce due to the lack of well-exposed structures. We present structures related to the development of the Bolfín fault in the Atacama Fault System (AFS), covering a scale...

Quantifying the microfracture damage surrounding faults and fractures is important for predicting the fluid flow properties of rock masses. Damage surrounding faults has been attributed to fault growth, geometric irregularities, and earthquake rupture. Up to now, earthquake rupture can only be inferred when pseudotachylyte is present, indicating sh...

The understanding of the nature of minor fractures produced during propagation and evolution of regional-scale faults is essential for comprehending of the processes prevailing during its development at all scales. This research is a characterization of the minor fractures associated with the Bolfín fault and a subsequent interpretation of the proc...